Methods for operating sensors of refrigerator appliances

ABSTRACT

Methods for operating a sensor of a refrigerator appliance are provided. In the methods, at least one of a detection threshold of the sensor, a power output of a transducer of the sensor, or a gain of an amplifier of the sensor can be adjusted. Through such adjustments, accuracy and precision of measurements taken with the sensor can be improved.

FIELD OF THE INVENTION

The present subject matter relates generally to refrigerator appliances with sensors for activating dispensers of the refrigerator appliances and methods for operating such sensors.

BACKGROUND OF THE INVENTION

Certain refrigerator appliances include a dispensing assembly for dispensing ice and/or liquid water. Such dispensing assemblies generally include an actuator, such as a button or paddle, or a sensor, such as an optical or ultrasonic sensor, for initiating a flow of ice and/or liquid water into a dispenser recess of the dispensing assembly. By pressing the actuator or triggering the sensor, a user can initiate the flow of ice and/or liquid water into a container, such as a cup or pitcher, positioned within the dispenser recess.

Certain dispensing assemblies having sensors also include features for automatically filling the container with ice and/or liquid water. The sensor can monitor a level of ice and/or liquid water within the container, and the dispensing assembly can terminate the flow of ice and/or liquid water into the container when the container is full or at a predetermined level. For such auto-fill features to operate properly, the sensor measures the container and its contents accurately and precisely.

Measuring the container and its contents with the sensor can be difficult. In particular, dispenser assemblies with auto-fill features can require precise tolerances between various components of the dispenser assembly in order to operate properly. For example, the dispenser assemblies' sensors can be set to a default setting if the various dispenser assemblies each have uniform components and such components are uniformly positioned relative to one another. However, component-to-component variation and assembly variation can arise during manufacture of such dispensing assemblies. In turn, such variations can hinder the sensors from accurately or precisely measuring the container and its contents in the default setting.

Accordingly, a method for operating a sensor in a dispenser assembly of a refrigerator appliance such that the sensor accurately and precisely measures a container within a dispenser recess of the dispenser assembly would be-useful. In particular, a method for operating a sensor in a dispenser assembly of a refrigerator appliance such that the sensor accurately and precisely measures a container within a dispenser recess of the dispenser assembly despite non-uniformities within the dispenser recess would be useful,

BRIEF DESCRIPTION OF THE INVENTION

The present subject matter provides methods for operating a sensor of a refrigerator appliance. In the methods, at least one of a detection threshold of the sensor, a power output of a transducer of the sensor, or a gain of an amplifier of the sensor can be adjusted. Through such adjustments, accuracy and precision of measurements taken with the sensor can be improved. Additional aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

In a first exemplary embodiment, a method for operating a sensor of a refrigerator appliance is provided. The sensor is directed towards a dispenser recess of the refrigerator appliance, The method includes arranging the dispenser recess of the refrigerator appliance in an empty configuration, receiving a baseline measurement of the dispenser recess from the sensor with the dispenser recess in the empty configuration, and adjusting a detection threshold of the sensor based at least in part upon the baseline measurement from the sensor.

In a second exemplary embodiment, a method for operating a sensor of a refrigerator appliance is provided. The sensor is directed towards a dispenser recess of the refrigerator appliance. The sensor has a transducer and a detector. The method includes arranging the dispenser recess of the refrigerator appliance in an empty configuration, receiving a baseline measurement of the dispenser recess from the detector of the sensor with the dispenser recess in the empty configuration, and adjusting a power output of the transducer of the sensor based at least in part upon the baseline measurement of the dispenser recess.

In a third exemplary embodiment, a method for operating a sensor of a refrigerator appliance is provided. The sensor is directed towards a dispenser recess of the refrigerator appliance. The sensor has a detector and an amplifier for amplifying a response of the detector. The method includes directing a first reference input to the detector of the sensor, determining an offset of the detector based at least in part on a response of the detector to the first reference input during the step of directing, sending a second reference input to the detector of the sensor, and adjusting a gain of the amplifier based at least in part upon a response of the detector to the second reference input during the step of sending.

In a fourth exemplary embodiment, a method for operating a sensor of a refrigerator appliance is provided. The sensor is directed towards a dispenser recess of the refrigerator appliance. The sensor has a detector and a transducer. The method includes directing a first reference input to the detector of the sensor, determining an offset of the detector based at least in part on a response of the detector to the first reference input during the step of directing, sending a second reference input to the detector of the sensor, and adjusting a power output of the transducer based at least in part upon a response of the detector to the second reference input during the step of sending.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

FIG. 1 provides a front, elevation view of an exemplary embodiment of a refrigerator appliance that may be used with the present subject matter.

FIG. 2 provides a front, elevation view of an ultrasonic sensor of the refrigerator appliance of FIG. 1.

FIG. 3 provides a schematic view of the refrigerator appliance of FIG. 1.

FIG. 4 is a graph of an exemplary background environment response of the ultrasonic sensor of FIG. 3 and exemplary detection thresholds of the ultrasonic sensor of FIG. 3.

FIG. 5 illustrates a method for operating a sensor of a refrigerator appliance according to an exemplary embodiment of the present subject matter.

FIG. 6 illustrates a method for operating a sensor of a refrigerator appliance according to an additional exemplary embodiment of the present subject matter.

FIG. 7 illustrates a method for operating a sensor of a refrigerator appliance according to another exemplary embodiment of the present subject matter.

FIG. 8 illustrates a method for operating a sensor of a refrigerator appliance according to a further exemplary embodiment of the present subject matter,

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

FIG. 1 provides a front, elevation view of an exemplary embodiment of a refrigerator appliance 100 that may be used with the present subject matter. Refrigerator appliance 100 defines a vertical direction V and extends between an upper portion 101 and a lower portion 102 along the vertical direction V. Refrigerator appliance 100 also includes a cabinet or housing 120 that defines chilled chambers for receipt of food items for storage. In particular, refrigerator appliance 100 defines a fresh food chamber 122 at upper portion 101 of refrigerator appliance 100 and a freezer chamber 124 arranged below fresh food chamber 122 on the vertical direction V, e.g., at lower portion 102 of refrigerator appliance 100. As such, refrigerator appliance 100 is generally referred to as a bottom mount refrigerator appliance. However, using the teachings disclosed herein, one of skill in the art will understand that the present subject matter may be used with other types of refrigerator appliances (e.g., side-by-side style or top mount style) or a freezer appliance as well. Consequently, the description set forth herein is for illustrative purposes only and is not intended to limit the present subject matter in any aspect.

Refrigerator doors 126 and 128 are rotatably hinged to an edge of housing 120 for accessing fresh food compartment 122. A freezer door 130 is arranged below refrigerator doors 126 and 128 for accessing freezer chamber 124. Freezer door 130 is coupled to a freezer drawer (not shown) slidably mounted within freezer chamber 124.

Refrigerator appliance 100 includes a dispensing assembly 110 for dispensing liquid water and/or ice. Dispensing assembly 110 includes a dispenser 114 positioned on or mounted to an exterior portion of refrigerator appliance 100, e.g., on refrigerator door 126. Dispenser 114 includes a discharging outlet 134 for accessing ice and liquid water. A paddle or actuator 132 is mounted below discharging outlet 134 for operating dispenser 114. In alternative exemplary embodiments, any suitable actuator may be used to operate dispenser 114, such as a button. A user interface panel 136 is provided for controlling the mode of operation. For example, user interface panel 136 includes a water dispensing button (not labeled) and an ice-dispensing button (not labeled) for selecting a desired mode of operation such as crushed or non-crushed ice.

Discharging outlet 134 and actuator 132 are an external part of dispenser 114 and are mounted in a dispenser recess 138 defined in an outside surface of refrigerator door 126. Dispenser recess 138 is positioned at a predetermined elevation convenient for a user to access ice or water and enabling the user to access ice without the need to bend-over and without the need to access freezer chamber 124. In the exemplary embodiment, dispenser recess 138 is positioned at a level that approximates the chest level of a user.

Dispenser assembly 110 also includes a first ultrasonic sensor 152 mounted to dispenser 114 and positioned within or adjacent dispenser recess 138. First ultrasonic sensor 152 is directed towards dispenser recess 138 and is configured for detecting a container within dispenser recess 138. First ultrasonic sensor 152 is discussed in greater detail below.

FIG. 2 provides a front, elevation view of first ultrasonic sensor 152 of refrigerator appliance 100. First ultrasonic sensor 152 includes an ultrasonic transducer 160 and an ultrasonic detector 162 for detecting a proximity or location of a container within dispenser recess 138. Ultrasonic transducer 160 is configured for generating high frequency sound waves and directing such sound waves towards dispenser recess 138 and objects located therein. Conversely, ultrasonic detector 162 is configured for detecting any high frequency sound waves reflected back towards first ultrasonic sensor 152 by objects within dispenser recess 138. As will be understood by those skilled in the art, the location, shape, alignment, or contents of a container within dispenser recess 138 may be determined by the amount of time between when ultrasonic transducer 160 sends out an ultrasonic sound wave and when ultrasonic detector 162 detects a reflection of such ultrasonic sound wave.

FIG. 3 provides a schematic view of refrigerator appliance 100. As may be seen in FIG. 3, refrigerator appliance 100 also includes a second ultrasonic sensor 154. Second ultrasonic sensor 154 may be constructed in a similar manner to first ultrasonic sensor 152 and include a similar ultrasonic transducer and ultrasonic detector. Thus, second ultrasonic sensor 154 may operate in a similar manner to first ultrasonic sensor 152. Like first ultrasonic sensor 152, second ultrasonic sensor 154 is directed towards dispenser recess 138 and is configured for detecting a container within dispenser recess 138. As an example, second ultrasonic sensor 154 can be mounted to dispenser 114, e.g., above (e.g., along the vertical direction V) dispenser recess 138 or adjacent discharging outlet 134. Second ultrasonic sensor 154 can be configured for detecting and/or locating a lip or a bottom of a container within dispenser recess 138. Second ultrasonic sensor 154 can also be configured for determining a height of contents within the container, e.g., relative to the lip or the bottom of the container.

Refrigerator appliance 100 further includes a controller 150. Operation of the refrigerator appliance 100 is regulated by controller 150 that is operatively coupled to control panel 138. In one exemplary embodiment, control panel 138 may represent a general purpose I/O (“GPIO”) device or functional block. In another exemplary embodiment, control panel 138 may include input components, such as one or more of a variety of electrical, mechanical or electro-mechanical input devices including rotary dials, push buttons, and touch pads. Control panel 138 may be in communication with controller 150 via one or more signal lines or shared communication busses.

Control panel 138 provides selections for user manipulation of the operation of refrigerator appliance 100. In response to user manipulation of the control panel 138, controller 150 operates various components of refrigerator appliance 100. For example, controller 150 is operatively coupled or in communication with actuator 132, user input panel 136, first ultrasonic sensor 152, and second ultrasonic sensor 154, such that controller 150 can operate such components. In particular, controller 150 is in communication with first and second ultrasonic sensors 152 and 154 and may receive signals from such components. Controller 150 can receive such signals in order to detect or locate a container within dispenser recess 138 as discussed above.

Controller 150 includes memory and one or more processing devices such as microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of refrigerator appliance 100. The memory can represent random access memory such as DRAM, or read only memory such as ROM or FLASH. The processor executes programming instructions stored in the memory. The memory can be a separate component from the processor or can be included onboard within the processor. Alternatively, controller 150 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.

As may be seen in FIG. 3, first ultrasonic sensor 152 includes an amplifier 164. Amplifier 164 is configured for amplifying or adjusting signals, e.g., from first ultrasonic sensor 152 to controller 150. As an example, adjusting a gain of amplifier 164 can adjust a magnitude of signals from ultrasonic detector 162 of first ultrasonic sensor 152. In particular, increasing the gain of amplifier 164 can increase the magnitude of signals from ultrasonic detector 162 of first ultrasonic sensor 152, Conversely, decreasing the gain of amplifier 164 can decrease the magnitude of signals from ultrasonic detector 162 of first ultrasonic sensor 152. It should be understood that second ultrasonic sensor 154 can include a similar amplifier.

FIG. 5 illustrates a method 500 for operating a sensor of a refrigerator appliance according to an exemplary embodiment of the present subject matter. As an example, method 500 may be used to operate first ultrasonic sensor 152 and/or second ultrasonic sensor 154 of refrigerator appliance 100 (FIG. 3), Thus, method 500 is described below in the context of operating first ultrasonic sensor 152. However, it should be understood that method 500 may be used to operate any suitable sensor, such as an infrared sensor, an optical sensor, a laser sensor, a capacitive sensor, or an inductive sensor, e.g., directed towards dispenser recess 138 of refrigerator appliance 100 for assisting operation of dispenser 114. Utilizing method 500, performance of first ultrasonic sensor 152 can be improved as discussed in greater detail below.

At step 510, dispenser recess 138 of refrigerator appliance 100 is arranged in an empty configuration. In the empty configuration, no containers, cups, glasses, or other similar objects are located within dispenser recess 138. Thus, the empty configuration corresponds to a configuration in which dispenser recess 138 is substantially empty, e.g., of foreign objects that could trigger first ultrasonic sensor 152.

At step 520, a background environment response or baseline measurement of dispenser recess 138 is received, e.g., by controller 150, from first ultrasonic sensor 152. In particular, the baseline measurement of dispenser recess 138 can be received from ultrasonic detector 162 of first ultrasonic sensor 152. Step 520 can be conducted at any suitable time. As an example, step 520 can be conducted at a factory during manufacture of refrigerator appliance 100, Alternatively or in addition thereto, step 520 can be conducted during installation or repair of refrigerator appliance 100, In certain exemplary embodiments, ultrasonic transducer 160 of first ultrasonic sensor 152 is deactivated at step 520, e.g., such that ultrasonic transducer 160 is not directing ultrasonic waves into dispenser recess 138

Dispenser recess 138 is in the empty configuration at step 520. Thus, the baseline measurement of dispenser recess 138 corresponds to a measurement of dispenser recess 138 in which dispenser recess 138 is substantially empty. As will be understood by those skilled in the art, the baseline measurement can correspond to the response of first ultrasonic sensor 152 to the particular arrangement of dispenser recess 138, e.g., to the components of dispenser 114 within dispenser recess 138.

FIG. 4 is a graph of an exemplary background environment response of first ultrasonic sensor 152. As may be seen in FIG. 4, the signal level of first ultrasonic sensor 152 varies as a function of distance from first ultrasonic sensor 152, The peaks in the exemplary background environment response of first ultrasonic sensor 152 can correspond to various features of dispenser 114 within dispenser recess 138, such as actuator 132.

At step 530, a detection threshold of first ultrasonic sensor 152 is adjusted, e.g., by controller 150, based at least in part upon the baseline measurement from step 520. In particular, the detection threshold of first ultrasonic sensor 152 can be adjusted such that the detection threshold is greater than the baseline measurement of step 520. The detection threshold of first ultrasonic sensor 152 can be adjusted such that the detection threshold is any suitable percentage greater than the baseline measurement of step 520, e.g., at all distances from first ultrasonic sensor 152. For example, the detection threshold of first ultrasonic sensor 152 can be adjusted such that the detection threshold of first ultrasonic sensor 152 is about two percent, about five percent, about ten percent, or about twenty percent greater than the baseline measurement of step 520.

The graph of FIG. 4 shows an exemplary adjusted detection threshold of first ultrasonic sensor 152 and an exemplary default detection threshold of first ultrasonic sensor 152. At step 530, controller 150 can adjust the detection threshold of first ultrasonic sensor 152 from the default detection threshold shown in FIG. 4 to the adjusted detection threshold shown in FIG. 4. In such a manner performance of first ultrasonic sensor 152 can be improved as discussed in greater detail below.

As will be understood by those skilled in the art, when an object, such as a container, is inserted into dispenser recess 138, the signal level of first ultrasonic sensor 152 will increase such that the signal level is greater than the baseline measurement of first ultrasonic sensor 152. Thus, when controller 150 receives a signal from first ultrasonic sensor 152 with a signal level greater than the baseline measurement, controller 150 can determine that the object is located or positioned within dispenser recess 138.

By adjusting the detection threshold of first ultrasonic sensor 152, e.g., from the default detection threshold shown in FIG. 4 to the adjusted detection threshold shown in FIG. 4, first ultrasonic sensor 152 can detect objects within dispenser recess 138 with greater accuracy and precision. In particular, by substantially matching a profile of the detection threshold of first ultrasonic sensor 152 to the baseline measurement of step 520 as shown in FIG. 4, smaller increases in the signal due to objects entering dispenser recess 138 can be detected with first ultrasonic sensor 152. In such a manner, first ultrasonic sensor 152 can detect objects within dispenser recess 138 with greater accuracy and precision, e.g., despite dispenser recess 138 having a different arrangement than that designed for the default detection threshold.

In additional exemplary embodiments, the detection threshold of first ultrasonic sensor 152 can include an upper detection threshold and a lower detection threshold as shown in FIG. 4 with the upper detection threshold being greater than the lower detection threshold. The upper and lower detection thresholds can he used to determine if first ultrasonic sensor 152 is working properly. In particular, the lower detection threshold can correspond to areas where signal response of first ultrasonic sensor 152 is known or can be predicted when first ultrasonic sensor 152 is functioning normally. Thus, if first ultrasonic sensor 152 does not generate signal strength sufficient to exceed the lower detection threshold in these areas, it can be inferred that first ultrasonic sensor 152 is not working properly. For example, areas close to first ultrasonic sensor 152 with higher signal strength can correspond to cross talk between ultrasonic transducer 160 and ultrasonic detector 162 that is generally present during operation of first ultrasonic sensor. Thus, if the signal strength of first ultrasonic sensor 152 in such areas does not exceed the lower detection threshold, it can be inferred that ultrasonic transducer 160 and/or ultrasonic detector 162 are not working properly. In such a manner, the upper and lower detection thresholds can assist with diagnosing first ultrasonic sensor 152, e.g., during repair and/or setup of first ultrasonic sensor 152.

FIG. 6 illustrates a method 600 for operating a sensor of a refrigerator appliance according to an additional exemplary embodiment of the present subject matter. As an example, method 600 may be used to operate first ultrasonic sensor 152 and/or second ultrasonic sensor 154 of refrigerator appliance 100 (FIG. 3). Thus, method 600 is described below in the context of operating first ultrasonic sensor 152. However, it should be understood that method 600 may be used to operate any suitable sensor, such as an infrared sensor, an optical sensor, a laser sensor, a capacitive sensor, or an inductive sensor, e.g., directed towards dispenser recess 138 of refrigerator appliance 100 for assisting operation of dispenser 114. Utilizing method 600, performance of first ultrasonic sensor 152 can be improved as discussed in greater detail below.

Certain steps of method 600 are substantially similar to method 500 and are discussed in light of corresponding steps described above. Like in step 510, dispenser recess 138 of refrigerator appliance 100 is arranged in the empty configuration at step 610. Further, like in step 520, the baseline measurement of dispenser recess 138 is received, e.g., by controller 150, from ultrasonic detector 162 of first ultrasonic sensor 152 with dispenser recess 138 in the empty configuration at step 620.

At step 630, a power output of ultrasonic transducer 160 of first ultrasonic sensor 152 is adjusted, e.g., by controller 150, based at least in part upon the baseline measurement of dispenser recess 138 from step 620. In particular, the power output of ultrasonic transducer 160 can be adjusted in order to set a response of ultrasonic detector 162 to ultrasonic waves from ultrasonic transducer 160 within a detection threshold of first ultrasonic sensor 152. Thus, rather than adjusting the detection threshold of first ultrasonic sensor 152 as in method 500, the power output of ultrasonic transducer 160 is adjusted in method 600.

As will be understood by those skilled in the art, increasing the power output of ultrasonic transducer 160 can correspond to increased or larger signals from ultrasonic detector 162. Conversely, reducing the power output of ultrasonic transducer 160 can correspond to decreased or smaller signals from ultrasonic detector 162. Thus, adjusting the power output of ultrasonic transducer 160 at step 630 can result in larger and/or smaller signals from ultrasonic detector 162. At step 630, the power output of ultrasonic transducer 160 can be adjusted, e.g., such that ultrasonic waves from ultrasonic transducer 160 cause signals from ultrasonic detector 162 to be greater than the detection threshold of first ultrasonic sensor 152 when an object is inserted into dispenser recess 138 without adjusting the detection threshold of first ultrasonic sensor 152. In such a manner, first ultrasonic sensor 152 can detect objects within dispenser recess 138 with greater accuracy and precision.

FIG. 7 illustrates a method 700 for operating a sensor of a refrigerator appliance according to another exemplary embodiment of the present subject matter. As an example, method 700 may be used to operate first ultrasonic sensor 152 and/or second ultrasonic sensor 154 of refrigerator appliance 100 (FIG. 3). Thus, method 700 is described below in the context of operating first ultrasonic sensor 152. However, it should be understood that method 700 may be used to operate any suitable sensor, such as an infrared sensor, an optical sensor, a laser sensor, a capacitive sensor, or an inductive sensor, e.g., directed towards dispenser recess 138 of refrigerator appliance 100 for assisting operation of dispenser 114. Utilizing method 700, performance of first ultrasonic sensor 152 can be improved as discussed in greater detail below.

At step 710, a first reference input is directed to ultrasonic detector 162 of first ultrasonic sensor 152. As an example, the first reference input can be a null input, such a zero voltage or current. The first reference input can be generated by any suitable source, such as a voltage source, a current source, or ultrasonic transducer 160. However, in certain exemplary embodiments, ultrasonic transducer 160 is deactivated during step 710.

At step 720, an offset of ultrasonic detector 162 is determined, e.g., by controller 150, based at least in part on a response of ultrasonic detector 162 to the first reference input during step 710. As will be understood by those skilled in the art, variations within circuitry or other components of first ultrasonic sensor 152 can generate an offset within responses of ultrasonic detector 162 to ultrasonic waves from ultrasonic transducer 160. The response of ultrasonic detector 162 to the first reference input during step 710 can correspond to the offset. With the offset determined at step 720, the offset can be accounted or corrected for within first ultrasonic sensor 152, e.g., during subsequent measurements with first ultrasonic sensor 152.

At step 730, a second reference input is sent to ultrasonic detector 162, e.g., by any of the sources described for step 710. The second reference input can be any suitable value, e.g., such that the second reference input is greater than the first reference input. As an example, the second reference input can be a sixty kilohertz AC signal directed to ultrasonic detector 162.

At step 740, the gain of amplifier 164 is adjusted based at least in part upon a response of ultrasonic detector 162 to the second reference input of step 730. In particular, the gain of amplifier 164 can be adjusted at step 740 in order to tune the response of ultrasonic detector 162 to a reference response when ultrasonic detector 162 receives the second reference input.

As will be understood by those skilled in the art, variations within circuitry or other components of first ultrasonic sensor 152 can cause ultrasonic detector 162 to generate various responses to the second reference input of step 730. Further, the reference response of ultrasonic detector 162 to the second reference input of step 730 can correspond to a desired output of ultrasonic detector 162 to the second reference input of step 730. By adjusting the gain of amplifier 164 to configure the response of ultrasonic detector 162 to the reference response when ultrasonic detector 162 receives the second reference input, first ultrasonic sensor 152 can detect objects within dispenser recess 138 with greater accuracy and precision, e.g., by having a more predictable response to ultrasonic waves from ultrasonic transducer 160.

FIG. 8 illustrates a method 800 for operating a sensor of a refrigerator appliance according to a further exemplary embodiment of the present subject matter. As an example, method 800 may be used to operate first ultrasonic sensor 152 and/or second ultrasonic sensor 154 of refrigerator appliance 100 (FIG. 3). Thus, method 800 is described below in the context of operating first ultrasonic sensor 152. However, it should be understood that method 800 may be used to operate any suitable sensor, such as an infrared sensor, an optical sensor, a laser sensor, a capacitive sensor, or an inductive sensor, e.g., directed towards dispenser recess 138 of refrigerator appliance 100 for assisting operation of dispenser 114. Utilizing method 800, performance of first ultrasonic sensor 152 can be improved as discussed in greater detail below.

Certain steps of method 800 are substantially similar to method 700 and are discussed in light of corresponding steps described above. Like in step 710, a first reference input is directed to ultrasonic detector 162 at step 810. Further, like in step 720, an offset of first ultrasonic senor 152 is determined at step 820 based at least in part on a response of ultrasonic detector 162 to the first reference input during step 810. In addition, like in step 730, a second reference input is sent to ultrasonic detector 162 at step 830.

At step 840, a power output of ultrasonic transducer 160 is adjusted, e.g., by controller 150, based at least in part upon a response of ultrasonic detector 162 to the second reference input at step 830. In particular, the power output of ultrasonic transducer 160 can be adjusted at step 840 in order to set the response of ultrasonic detector 162 to signals from ultrasonic transducer 160 within a detection threshold of first ultrasonic senor 152. Thus, rather than adjusting the gain of ultrasonic detector 162 as in method 700, the power output of ultrasonic transducer 160 is adjusted in method 800.

As will be understood by those skilled in the art, increasing the power output of ultrasonic transducer 160 can correspond to increased or larger signals from ultrasonic detector 162. Conversely, reducing the power output of ultrasonic transducer 160 can correspond to decreased or smaller signals from ultrasonic detector 162. Thus, adjusting the power output of ultrasonic transducer 160 at step 840 can result in larger and/or smaller signals from ultrasonic detector 162. Further, the power output of ultrasonic transducer 160 can be adjusted at step 840, e.g., such that ultrasonic waves from ultrasonic transducer 160 cause signals from ultrasonic detector 162 to be greater than the detection threshold of first ultrasonic sensor 152 when an object is inserted into dispenser recess 138. In such a manner, first ultrasonic sensor 152 can detect objects within dispenser recess 138 with greater accuracy and precision.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A method for operating a sensor of a refrigerator appliance, the sensor directed towards a dispenser recess of the refrigerator appliance, the method comprising: arranging the dispenser recess of the refrigerator appliance in an empty configuration; receiving a baseline measurement of the dispenser recess from the sensor with the dispenser recess in the empty configuration; and adjusting a detection threshold of the sensor based at least in part upon the baseline measurement from the sensor,
 2. The method of claim 1, wherein said step of adjusting comprises adjusting the detection threshold of the sensor such that the detection threshold of the sensor is greater than the baseline measurement from the sensor.
 3. The method of claim 1, wherein the sensor is an ultrasonic sensor having an ultrasonic transducer and an ultrasonic detector, said step of receiving comprising receiving the baseline measurement of the dispenser recess from the ultrasonic detector of the ultrasonic sensor with the dispenser recess in the empty configuration.
 4. The method of claim 3, wherein the ultrasonic transducer of the ultrasonic sensor is deactivated during said step of receiving.
 5. The method of claim 1, wherein the detection threshold comprises an upper detection threshold and a lower detection threshold, the upper detection threshold being greater than the lower detection threshold,
 6. A method for operating a sensor of a refrigerator appliance, the sensor directed towards a dispenser recess of the refrigerator appliance, the sensor having a transducer and a detector, the method comprising: arranging the dispenser recess of the refrigerator appliance in an empty configuration; receiving a baseline measurement of the dispenser recess from the detector of the sensor with the dispenser recess in the empty configuration; and adjusting a power output of the transducer of the sensor based at least in part upon the baseline measurement of the dispenser recess.
 7. The method of claim 6, wherein said step of adjusting comprises adjusting the power output of the transducer in order to set a response of the detector to signals from the transducer within a detection threshold of the sensor,
 8. The method of claim 6, wherein the sensor is an ultrasonic sensor, the transducer of the sensor is an ultrasonic transducer, and the detector of the sensor is an ultrasonic detector.
 9. The method of claim 6, wherein the transducer of the sensor is deactivated during said step of receiving.
 10. A method for operating a sensor of a refrigerator appliance, the sensor directed towards a dispenser recess of the refrigerator appliance, the sensor having a detector and an amplifier for amplifying a response of the detector, the method comprising: directing a first reference input to the detector of the sensor; determining an offset of the detector based at least in part on a response of the detector to the first reference input during said step of directing; sending a second reference input to the detector of the sensor; and adjusting a gain of the amplifier based at least in part upon a response of the detector to the second reference input d said step of sending.
 11. The method of claim 10, wherein the first reference input is a null input.
 12. The method of claim 10, wherein the second reference input is greater than the first reference input.
 13. The method of claim 10, wherein the sensor is an ultrasonic sensor and the detector of the sensor is an ultrasonic detector.
 14. The method of claim 10, wherein said step of adjusting comprises adjusting the gain of the amplifier in order to tune the response of the detector to a reference response when the detector receives the second reference input.
 15. A method for operating a sensor of a refrigerator appliance, the sensor directed towards a dispenser recess of the refrigerator appliance, the sensor having a detector and a transducer, the method comprising: directing a first reference input to the detector of the sensor; determining an offset of the detector based at least in part on a response of the detector to the first reference input during said step of directing; sending a second reference input to the detector of the sensor; and adjusting a power output of the transducer based at least in part upon a response of the detector to the second reference input during said step of sending.
 16. The method of claim 15, wherein the first reference input is a null input.
 17. The method of claim 15, wherein the second reference input is greater than the first reference input.
 18. The method of claim 15, wherein the sensor is an ultrasonic sensor, the transducer of the sensor is an ultrasonic transducer, and the detector of the sensor is an ultrasonic detector.
 19. The method of claim 15, wherein said step of adjusting comprises adjusting the power output of the transducer in order to set the response of the detector to signals from the transducer within a detection threshold of the sensor. 